Mike Tyson -- Abandoned Mansion Sold to Church ... For $750k Steal!

The price was right for Mike Tyson's former Ohio palace to get snatched up by a fledgling church ... which got a very sweet deal for the 58-acres -- and we've learned Tyson will have an open invitation.

Pastor Nick Dejacimo with The Living Word Sanctuary tells TMZ Sports they dropped $750k on the land and the house ... which is 33,000 sq. ft. Yeah, that's a lot of money ... until you consider it was valued at $1.3 million in 1999.

Pastor Nick says the place is almost ready to move in -- "The skylights, arches, and windows in the pool area, it literally looks like a church." As for the dilapidated pool ... he says it will be filled in and converted to the sanctuary.

He adds his humble congregation of 140 has saved 9 years worth of tithing donations in order to make the purchase. In addition to the church ... they plan to renovate part of the land into a workout facility with a jogging path.